1. Field of the Disclosure
The invention relates, in general, to couplings for the connection of lines, such as, in particular, flexible lines, to one another or for the coupling of flexible lines to fittings. In particular, the invention relates to self-sealing couplings or dry disconnect couplings, that is, couplings whose coupling parts seal the lines when the coupling is disconnected.
2. Description of the Related Art
Known from DE 299 11 281 U1 is a quick-action coupling for connecting or joining flexible lines, which comprises an inserting part and a receiving part. The parts can be locked together in a releasable and fluid-tight manner. Arranged in the two parts of the quick-action coupling in the flow channel is a spring-loaded valve with closing elements, the closing elements being loaded with compression springs. These closing elements in the form of balls, for example, remain open in the state in which the inserting part and receiving part are coupled together. When these coupling parts are disconnected, the closing elements are then pressed into their valve seat by the compression springs and, in this way, seal off the line connected with the respective coupling part.
In general, even in the case of self-sealing couplings, there is the problem that, when the coupling parts are disconnected, contents can leak from the lines. Although the valves in the coupling parts prevent the lines from remaining permanently open after disconnection has occurred, of course, leakage of line contents can always still occur during the closing operation of the valves when they are disconnected.
Especially in the case of cryogenic fluids, freezing of the line contents or of air moisture on the valves can also occur when they are disconnected. As a result of this, the valves may no longer close tightly and leakage of the line contents is no longer stopped. This is particularly critical also in relation to the danger of fire when combustible media are being conducted.